Treatment of motor fuel



Patented Jan. 4, 1938 FFICE 2,104,049 I TREATliIENT F MOTOR FUEL Jacque O. Morrell, Chicago, Ill., assignor to Universal Oil Products Company,

Chicago, 111., a

corporation of Delaware No Drawing. Application July 29, .1932, y Serial No. 626,178

9 Claims.

storage under the influence of light and air there,

10 is substantially no deterioration in regard to knock rating or the development of color and gums or other undesirable characteristics.

Thetypes of tars with which the invention is concerned vary in character and composition according to variations in the primary carbonaceous material from which they are produced and also vary with the conditions'of distillation, particularly in regard to the pressures, temperatures and rates of heating employed. These primary tars 0 contain varying proportions of the principal hydrocarbon groups, to wit, paraflins; olefins, naphthenes and aromatics, and, also contain nitrogen, oxygen and sulphur compounds. In cracking such mixtures, the products obtained will depend upon the relative proportions of the classes of hydrocarbons and hydrocarbon derivatives which are present, the boiling ranges of the, different groups and the conditions employed in cracking.

In regard to the products from cracking the nitrogen, oxygen and sulphur derivatives, particularly in the presence of'preponderating amounts of hydrocarbons, less information is available but in general it may be assumed that the various groups of derivatives produce lower boiling compounds of the same type although their decomposition is influenced to some extent by the products of the hydrocarbon decomposition reactions.

In one specific embodiment, the invention comprises cracking primary tars containing phenolic compounds under elevated temperatures and pres-.

sures to produce low boiling motor fuel fractions,

treating said motor fuel fractions with alkalies to remove phenols, separating phenols from the alkali solutions by acidification thereof and returning regulated amounts of the selected fractions of the separated phenols to the treated motor fuel fractions, preferably after first refining the same by further well known treatment such as with sulphuric acid,-to inhibit the'loss of valuable properties therein during storage under the influence of light and air. -The'motor fuel fractions may be further treated with dilute acids which are later neutralized with alkali and the recovered basic materials may then be added to the treated motor fuel in regulated amounts. Inhibitors are to be distinguished from antiknock agents in that the true antiknock agent modifies the combustion of fuel in an internal 5 combustion engine cylinder but does not necessarily prevent the development of undesirable characteristics under storage. In fact, numerous well defined antikn'ock agents are themselves unstable instorage and the gasoline to which they 10 are added needs further additions of true inhibitors to stabilize the increased antiknock value produced by the addition of the antiknock agent. Furthermore, it is usuallynecessary to use much higher percentages of reagents to prevent knocking than is necessary in inhibiting deterioration and depreciation of the gasoline so that it will be seen that in the great majority of cases the action of antiknock agents is distinct from that of true inhibitors such as the phenolic mixtures used in the present invention.

Numerous compounds of a phenolic character have been employed as inhibitors, the ones most generally used being individual chemical compounds produced by synthesis from simpler materials or by tedious and expensive processes which effect their separation from primary tars. The present process is self-contained in that the inhibiting materials are a product of the process so 30 that greater economy is possible than in the use of such materials manufactured by special .outside processes. The amount of phenolic fractions possessing inhibiting value which are present in the cracked products from primary tars is usually 35 in excess of that required for properly stabilizing the treated motor fuel so that only relatively small quantities and select fractions of the tar acids extracted by caustic alkalies are necessary to effect the required stabilization of properties. 40 Such fractions may be produced by redistilling the separated tar acids toproduce a plurality of overhead cuts which may then be tested to see which cut or blend of cuts is of the greatest value. Such' redistillation will also leave behind as a residue any heavy pitchy or tarry materials which would add color to the treated motor fuel even when used in small amounts of the order of 0.05%.

The following'examples of results obtainable 5 bythe use of the process of the invention on coal, wood and lignite tars, respectively, will serve to .show its-commercial advantages.

A coal tar derived from Ohio-Indiana bituminous coal by low temperature distillation was cracked at 100 pounds pressure and 800 F. a The analysis of the tar is given in the following table:

Sp. Gr 1.0794

I. B. P 240 F.

Flash 130 F. Cleveland open cup Fire 180 F. Cleveland open cup Furol vise. 122 F 70sec.

This tar yielded, under the conditions stated, 33.9% of motor fuel boiling range fractions containing 35% tar acids or 22% of motor fuel fractions on an acid-free basis. In the present instance, the solution of tar acids was acidified and the acids distilled at atmospheric pressure to produce fractions corresponding to 25 C. boiling ranges beginning at 225 C. These fractions were tried separately upon the acid and alkali refined motor fuel to determine their value as inhibitors and it was found that the use of 0.05% of any of the fractions in the treated gasoline was ample to stabilize and conserve the valuable properties,

such as color, low gums and antiknock value. The fraction of highest value in preventing deterioration of the gasoline was found to be that boiling between 250 and 275 C., and the use of this fraction raising the induction period in the oxyen bomb test from 50 minutes 120400 minutes, which is inexcess of the ordinarily required 240 minutemaximum.

As another example of the use of the process, a wood tar derived from the distillation of Douglas fir was cracked under a pressure of 120 pounds per square inch and-a temperature of approximately 775 F. The analysis of the original tar is given in the following table:

. Table 2 Specific gravity 1.061 A. P. I. gravity 1.7

' Initial boiling point: a 1 F 240 C 116 Per cent over C. 10 172 20 228 30 263 Coke, per cent by weight 14.4 Acidity Per cent per cent Aqueous distillate 15.5 0.4 Oil 61.5 Coke, gas and loss 23.0

.fuel on an acid-free basis.

There was produced by this operation 27.2% of rerun to produce a total yield of 33% of tar acidfree motor fuel fraction.

As before, the crude motor fuel was treated with sulphuric acid and caustic soda, the tar acids separated from the alkali solution and fractionated into comparatively narrow'boiling range cuts. All 25 C. fractions between 225 C. and 325 C. raised the induction period of the treated gasoline from 45 to above 240 minutes, the fraction from 275 to 300 having the greatest elliciency. v

The following example gives data on the application of the process to the production of stable motor fuel from lignite tar.

Properties of lignite tar Water (A. s. 'r. M. method 300.12)--per cent 1.2

Taracids-per cent 25.1 Tar bases-per cent 0.9 100 cc. A. S. T. M. distillation I. L. P., F. 210 5% 365 30 507 40 558 50 613 60 647 70 675 6'75 -4 684 E. P., "F 693 Percent Over 96.0 Coke by wt 4.3 400 F. 8.0 437 F. 14.5 572 F. 41.0

The tar was cracked under a pressure of pounds per square inch and a temperature of 750 to 800 F., giving the following yields of products:

' Per cent Gasoline fraction to 392 F 33.5 Intermediate gas oil recycle stock .4... 34.8 Coke gas and loss 30.1 Water 1.6

' Recycle Properties Gasoline Stock Gravity A. P. I 51.6 29.6 Gum, mgs./i00 cc. (copper dish). 382 Suiphurpercent.. 0. 28 0. 30 Octane N 66 2). 1 19. 1 0. 7 0. 6 123 404 176 417 198 .426 229 437 $5 463 90 350 572 E. P., "F 392 644 Percent over 98. 5 Percent bottoms. l. 5

Gravity A. P. I 17.1 Flash (Cleveland open cup) F Fire (Cleveland open cup) F Flash (Pensky-Martens) F 125 Viscosity, Furol@122 F., sec 12 Sulphur-per cent 0.41 Cold test F 80 B. S. 8: W.per cent 3.4

The gasoline was treated successively with sulphuric acid and 10% sodium hydroxide to remove the tar bases and tar acids. After this treatment, the gasoline was furthertreated in liquid phase at ordinary temperatureswith ten pounds per barrel of 93% sulphuric acid, neutralized with caustic soda and rerun with fire and steam. The gasoline thus produced had the following properties:

By treating the gasoline with only half the acid above shown, that is, 5 pounds per barrel instead of 10, the color stability was found to be around and the gum content in the neighborhood of 50' mgs. whilethe octane number was approximately 70 to 72%. The alkali solution of the tar acids was acidified and redistilled, the fraction boiling from 240 to 300 C. being used as inhibiting material in an amount 'equal to 0.05%. The

gasoline after the addition of this particular fraction of tar acids was found' then to have sub-v stantially the same properties as the gasoline resulting from the 10 pound acid treatment in respect to color, color stability, gums and sulphur while the octane number was still above 70%.

-The foregoing specification and examples have shown the value of the process in producing motor fuel which is effectively stabilized by the use of by-products of the overall operation. While the specification and examples are sufficient to accurately define the process and show its commercial advantages, neither is to be construed cracked distillate, distilling the separated phenolic subs'tancesand removing the cutthereof of highest inhibiting value, and adding such cut in small amount to the distillate as an inhibitor therefor.

2. A process for producing stabilized motor fuel distillate from tars containing phenolic compounds which comprises cracking the tar, sepfuel distillate from tars containing phenolic com-' arating phenolic substances from the resultant cracked distillate, distilling the separated phenolic substances and removing therefrom a cut boiling between 240 C. and 300 C., and adding such cut in small amount to the distillate as an inhibitor therefor.

3. A process for producing stabilized motor pounds which comprises cracking the tar, extracting phenolic substances from the resultant cracked distillate, separating from the extract a select inhibitor fraction, and adding such fraction' in small amount to the distillate as an inhibitor therefor. 1

4. In a process of stabilizing against gum formation, cracked hydrocarbon spirits ofthe type obtained by cracking hydrocarbons which produce substantial quantities of phenolic substances in the cracked gasoline, the steps of extracting the phenolic substances from the cracked gasoline and purifying the cracked gasoline by ordinary refinery treatment, separating by fractionation a portion of the phenolic extract having strong inhibiting propertiesand readding a quantity of the phenolic substance to the refined cracked gasoline suflicient to substantially stabilize the same against gum formation.

5. In the treatment of cracked hydrocarbon I distillates of the type obtained by cracking hydrocarbons which produce substantial quantities of phenolic substances in the cracked distillate, the steps of extracting the crude phenolic substances, converting the same to more highly effective inhibitor bodies, and readding the same to the distillate in quantity sufficient to stabilize the distillate against gum formation.

6. A process for producing stabilized motor fuel distillate from hydrocarbon material containing phenolic compounds, which comprises cracking the hydrocarbon material, extracting phenolic substances from resultant cracked products, separating ,from the extract a select inhibitor fraction, and adding such fraction in small amount to the overhead distillate of the cracking as, an inhibitor therefor.

'7. A method for treating cracked hydrocarbon distillates obtained by cracking hydrocarbon materials which produce substantial quantities of phenolic substances in the cracked distillate; said method comprising the steps of extracting phenolic substances from the distillate, separating from the extract a, select inhibitor fraction, and re-adding such fraction to the distillate in sufficient amount to stabilize the distillate substantially against gum formation.

8. A method for treating cracked hydrocarbon distillates obtained by cracking hydrocarbon 'materials which produce substantial quantities of phenolic substances in the cracked distillate, said method comprising the steps of extracting phenolic substances from the distillate, producing from the resultant extract .a material of high gum-inhibiting properties, and re-adding such material to the distillate insufficient amount to stabilize the distillate substantially against gum formation.

9. A method for treating cracked hydrocarbon distillates obtained by cracking hydrocarbon materials which produce substantial quantities of phenolic substances in the cracked distillate, said method comprising the steps of extracting phenolic substances from'the distillate, fractiona fraction having strong inhibiting properties, and re-adding such fraction to the distillate in sufflcient amount to stabilize the distillate substantially against gum formation.

JACQUE C. MORREIL.

, ating the resultant extract to separate therefrom 

